Of course, with vector graphics, you can work on a very small scale, until 
you get it right.  Then make full size.  The problem is that often times, 
something that looks great at a small size, might look quite boring after 
scaling up -- especially when going from computer screen to 30 sq ft.

First, note that I just use inkscape as a hobby, and perhaps professionals 
will have some kind of procedure that that works better.

I would start on a small scale (computer screen/Inkscape window), and work 
out the basic design, and various ratios for the fish scales, and settings 
in the Tiled Clones dialog.

Once you have that sorted out, I would decide what constitutes one unit of 
the pattern.  I mean, I would guess it would be easier to have a set of say 
20 x 30 fish scales, that repeats across the whole 30 sq ft area.....or 
depending on the size of the fish scales -- I don't know if you're thinking 
of real size fish scales (perhaps the size of a fingernail), or if they will 
be giant scales, more like 1 to 3 inch size fish scales.

Of course, with Inkscape's Tiled Clones dialog, you wouldn't necessarily 
have to have any repeated patterns.  It could be unique as a whole.  But I 
think having a repeated pattern would allow you to work on 1 unit of the 
design, at the full scale, to get the design so that it looks good at the 
full size.

I would suggest starting with the manual:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Tiles.html

And here's a good tutorial, although it's not specifically for such a large 
project, it probably has all the details you need:
http://verysimpledesigns.com/vectors/inkscape-tutorial-seamless-patterns.html.

And here's another good one:
http://www.paulfriedl.com/all-portfolio-list/tileable-pattern-tutorial/

I hope that's helpful :-)

All best,
brynn

From: John Fisher
Sent: Wednesday, October 08, 2014 11:33 AM
To: inkscape User Community
Subject: [Inkscape-user] Suggestions for tiling a car wrap

I am building a tiny electric car, and it has bikini-level fiberglas body 
components, about 30 sq ft. We've settled on a fish-scale graphic design to 
be done with vinyl car-wrap.

I've never done a big tiling job, and I'd like to have a lot of color&detail 
variation, very much like a real fish. Any suggestions, or a tutorial I 
missed?